ross94 Posted April 20, 2018 Report Share Posted April 20, 2018 Dear all, Rear brake pedal has no feel and just doesn't do anything. I have tried all possible ways to bleed the rear brake system but I can't get to remove the air bubbles (or at least what it seems to be the issue). Have tried normal bleeding as in pushing the pedal several times and when holding it down opening the bleed nipple but no luck - air is getting out but it's never enough. Tried pressure bleeding and even vacuum bleeding as well using a syringe and a piece of transparent pipe and also no luck one thing i noted when vacuum bleeding was that air bubbles did disappear slightly but kept on coming like it's getting air from somewhere. What could this be? Any sort of help is highly appreciated guys as this is my first trial and I can't wait to ride it. Thanks in advance, Ross Quote Link to comment Share on other sites More sharing options...
section swept Posted April 20, 2018 Report Share Posted April 20, 2018 (edited) Check the brake master cylinder around the seal for signs of fluid leakage and corrosion. Check for signs of fluid leakage on the rear caliper around the pistons. If all appears to be clean and clear of leaks.....the seals can allow air into the circuit in some instances but no fluid escapes....Gently eases the brake pads back off the disc into the caliper and use either thin strips of plastic or alluminium to go in the gap between the pad and the disc. Make sure the caliper pistons are clean on their exposed surface before doing this. Now go through the bleed process again, fill the reservoir with fresh clean fluid...never re use fluid that’s been bled through and don’t shake the fluid container, this will aerate the fluid and it will need to settle for a long time. If the fluids been exposed to the atmosphere it will draw in moisture from the atmosphere...hygroscopic....fully synthetic fluid is less likely to be affected but nonetheless less treat with care. Is the bleed nipple creating a good seal/seat when gently nipped up home? With a clear tube attached to the nipple and the open end immersed in a small amount of fluid in a clear pot you can start to bleed. Open the nipple and operate the brake lever fully down and observe the fluid coming out of the pipe into the pot, hold the lever down and close the nipple. Repeat the process several times until no air is seen in the bleed pipe. Tighten the nipple gently. Operate the lever, you should feel resistance almost immediately. If this is the case you can now remove the pad packing and then operate the brake lever pumping the pads into contact with disc, at which point the lever should feel quite firm. Check the master cylinder push rod free play and set to man. spec. Too little free play will eventually cause the fluid to get hot, expand and force the brake into being on until it all cools down again. If this doesn’t work then I’m afraid you will need to either replace the master cylinder complete or fit a seal kit, and if there’s no improvement a caliper/seal kit, if available to you. It’s a simple circuit and blanking off the flexible pipe at the caliper end should help you eliminate one or the other. Re reading you writing, vacuum bleeding is a good method and using a syringe to bleed is a good method, providing the flex pipe, caliper and m/cylinder are in good order. Hope you sort it, let me know?? Edited April 20, 2018 by section swept Additional script Quote Link to comment Share on other sites More sharing options...
dan williams Posted April 20, 2018 Report Share Posted April 20, 2018 Very good advice above. For what it's worth none of us likes bleeding the rear brake. It's always misery. Quote Link to comment Share on other sites More sharing options...
section swept Posted April 20, 2018 Report Share Posted April 20, 2018 1 minute ago, dan williams said: Very good advice above. For what it's worth none of us likes bleeding the rear brake. It's always misery. Jaguars with Dunlop braking systems were a real pain, taking the calipers off and holding them upside down, you would not believe the performance some systems required. I still find it hard to believe that some of the Italian superbikes need the same trick to achieve a decent brake. Quote Link to comment Share on other sites More sharing options...
section swept Posted April 20, 2018 Report Share Posted April 20, 2018 Additionally once a good firm feel is established, by holding the pressure on for 12 or more hours this removes the microscopic air bubbles and really gives the brake lever/pedal an even firmer feel. Quote Link to comment Share on other sites More sharing options...
misscrabstick Posted April 20, 2018 Report Share Posted April 20, 2018 37 minutes ago, section swept said: Jaguars with Dunlop braking systems were a real pain, taking the calipers off and holding them upside down, you would not believe the performance some systems required. I still find it hard to believe that some of the Italian superbikes need the same trick to achieve a decent brake. They fitted calipers not specifically designed for the angle they mounted them at, that made the bleed nipple in the wrong place to purge the caliper of all the air bubbles easily. Quote Link to comment Share on other sites More sharing options...
section swept Posted April 20, 2018 Report Share Posted April 20, 2018 2 minutes ago, misscrabstick said: They fitted calipers not specifically designed for the angle they mounted them at, that made the bleed nipple in the wrong place to purge the caliper of all the air bubbles easily. Exactly, some dimwit had the bleed nipples on the lower half of the caliper. We used to refer to that kind of mistake as coming from the f@#£ up department. And don’t mention the handbrake, MOT testers had to make an exception for what was a secondary brake, I’d call it a wishing brake! Quote Link to comment Share on other sites More sharing options...
misscrabstick Posted April 20, 2018 Report Share Posted April 20, 2018 1 minute ago, section swept said: Exactly, some dimwit had the bleed nipples on the lower half of the caliper. We used to refer to that kind of mistake as coming from the f@#£ up department. And don’t mention the handbrake, MOT testers had to make an exception for what was a secondary brake, I’d call it a wishing brake! I have had the horrible experience of dropping out the entire back end on a v12 E type to service the handbrake caliper! what were they thinking? Quote Link to comment Share on other sites More sharing options...
section swept Posted April 20, 2018 Report Share Posted April 20, 2018 (edited) 27 minutes ago, misscrabstick said: I have had the horrible experience of dropping out the entire back end on a v12 E type to service the handbrake caliper! what were they thinking? THINKING now that’s a new word for them (in the past at Jaguar) to conjure with. More likely designed by committee and approved by the doorman! I used to service the XJS company car that the Aston Martin Media Manager used to run...work that one out! He wanted to know why he got rear wheel spin at 80 mph in the wet...I ask you?.. We even had a Jaguar field engineer out to confirm the car had the high ratio diff fitted...prop turns to road wheel turns multiplied by the number of stripes on the engineers tie. This car it turns out was his wife’s shopping car, he bought from us a ......wait for it.....no I’m considering my options here....wait....a....( this is like the stupid part in any games show where they build up the boredom..I mean tension)......wait I’m straining this out now......ROVER SD1 3’500 Vee 8 Van Den Plas....there I’ve said it....now did this Aston Martin Media Manager have style and panache, an accute eye for things beautiful and alluring....NOPE...never mind the fact that he wasn’t offered an Aston....any wonder Ford had to bail AM out. In another perverse world our AM salesman drove as a company car....wait for it.......wait........a.......wait...........Princess 1.7L that’s the ‘O’ series engine laddie be proud.....imagine turning up at a prospective AM buyers residence in that pile of c#@£! Edited April 20, 2018 by section swept Quote Link to comment Share on other sites More sharing options...
misscrabstick Posted April 20, 2018 Report Share Posted April 20, 2018 1 minute ago, section swept said: THINKING now that’s a new word for them (in the past at Jaguar) to conjure with. More likely designed by committee and approved by the doorman! I used to service the XJS company car that the Aston Martin Media Manager used to run...work that one out! He wanted to know why he got rear wheel spin at 80 mph in the wet...I ask you?.. We even had a Jaguar field engineer out to confirm the car had the high ratio diff fitted...prop turns to road wheel turns multiplied by the number of stripes on the engines tie. This car it turns out was his wife’s shopping car, he bought from us a ......wait for it.....no I’m considering my options here....wait....a....( this is like the stupid part in any games show where they build up the boredom..I mean tension)......wait I’m straining this out now......ROVER SD1 3’500 Vee 8 Van Den Plas....there I’ve said it....now did this Aston Martin Media Manager have style and panache, an accute eye for things beautiful and alluring....NOPE...never mind the fact that he wasn’t offered an Aston....any wonder Ford had to bail AM out. In another perverse world our AM salesman drove as a company car....wait for it.......wait........a.......wait...........Princess 1.7L that’s the ‘O’ series engine laddie be proud.....imagine turning up at a prospective AM buyers residence in that pile of c#@£! No wonder our car making industry is very dead, I started in the trade in the early 80's and have had many of these "gems" pass through the workshops I have worked in, good days really, workshop life is so different now, tearing your hands to bits trying to get to a stupidly placed EGR valve etc... Quote Link to comment Share on other sites More sharing options...
arnoux Posted April 20, 2018 Report Share Posted April 20, 2018 When you use a vacuum bleeder (by far the best way IMHO) you will always see air bubbles in a transparent line. It's pulling a little air from between the seal of the bleeder and the tube. So don't worry about it - you will never see clear fluid in the transparent line. But it will bleed heaps faster than ANY other method. You can purchase cheap plastic bleeder kits from EvilBay for not much, but after doing 100's of brakes over the years I can advise get one of the brass bodied pistol grip types. It is one of the best tools in our workshop, and so fast and easy. We have one in the workshop, and one in the van at events, and they are GOLD. Quote Link to comment Share on other sites More sharing options...
dan williams Posted April 21, 2018 Report Share Posted April 21, 2018 I know it had no bearing on the original poster’s question but that was fascinating. I’ve never worked on a brit car. It sounds, “interesting”. Quote Link to comment Share on other sites More sharing options...
section swept Posted April 21, 2018 Report Share Posted April 21, 2018 11 hours ago, misscrabstick said: No wonder our car making industry is very dead, I started in the trade in the early 80's and have had many of these "gems" pass through the workshops I have worked in, good days really, workshop life is so different now, tearing your hands to bits trying to get to a stupidly placed EGR valve etc... No change there then! I started my apprenticeship in 1966 in a small garage with three mechanics and me, and even then we reconned that after the initial design of a car was ok’d for production it was then passed to the department of sharp edges and impossible corners to hinder access or better know as the ‘cock up department’ Strangely enough in the Marine industry sport boats and upto 50 footers these to can prove to be virtually impossible to get at vital components when needed. Cam belt access on many of the latest cars and vans is dammed awkward, hurrah for the reinvention of the timing chain, and now the wet belt from Mr Ford. Keep yer tools clean??? Quote Link to comment Share on other sites More sharing options...
section swept Posted April 21, 2018 Report Share Posted April 21, 2018 8 hours ago, dan williams said: I know it had no bearing on the original poster’s question but that was fascinating. I’ve never worked on a brit car. It sounds, “interesting”. Working on US cars can be challenging too but more of a pleasure as they don’t appear so often.... Quote Link to comment Share on other sites More sharing options...
lineaway Posted April 23, 2018 Report Share Posted April 23, 2018 Before giving up. You need to try new pads first. Most of the time it is just worn pads in the first place. Quote Link to comment Share on other sites More sharing options...
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